1. Field of the Invention
The present invention relates to a buckle and more particularly, to a side release buckle.
2. Description of the Related Art
Belts and straps are intensively used to collars, harnesses, baby cradles, backpacks, safety helmets, slippers, life vests, cargoes, vehicle seats, etc. For joining belts or the ends of a belt, a buckle may be used. Various buckles have been disclosed and commercialized.
FIGS. 1 and 2 show a typical belt buckle. This design of belt buckle is called “side release buckle” because it is to be unlocked from the two opposite lateral sides. As illustrated, the side release buckle 50 is comprised of a male buckle member 51 and a female buckle member 52. The male buckle member 51 comprises two axially extended locking bars 53a,53b and a center bar 54 spaced between the locking bars 53a,53b. The female buckle member 52 comprises a receiving open chamber 55 for receiving the locking bars 53a,53b and the center bar 54, and two side notches 56a,56b respectively formed in the two opposite lateral sidewalls thereof for retaining the locking bars 53a,53b. When inserted the male buckle member 51 into the receiving open chamber 55 of the female buckle member 52, the locking bars 53a,53b are forced by their resilient material property into engagement with the side notches 56a,56b to lock the male buckle member 51 to the female buckle member 52. When the user squeezed the locking bars 53b,53b inwards with the fingers to disengage the locking bars 53a,53b from the side notches 56a,56b, the male buckle member 51 is unlocked from the female buckle member 52.
The male buckle member 51 and female buckle member 52 of the aforesaid side release buckle 50 are injection-molded from plastics. Because the side release buckle 50 is made of plastics, the tensile strength of the side release buckle 50 is not very high. In order to have the locking bars 53a,53b be easily disengaged from the side notches 56a,56b, the cross-sectional area of the locking bars 53a,53b must be limited. Due to a small cross-sectional area, the locking bars 53a,53b are the weakest part of the male buckle member 51. When the side release buckle 50 receives a pulling force surpassed the tensile strength of the locking bars 53a,53b, the locking bars 53a,53b will break.
As stated above, belts and straps may be used with a side release buckle in any of a variety of products. Some designs may have to receive a high pulling force, and some others may not. The side locking design of the aforesaid side release buckle is sufficient for most occasions of use. However, when the aforesaid side release buckle is used in a harness or collar for dog, the engagement between the locking bars of the male buckle member and the side notches of the female buckle member may be insufficient to support a sudden stretching force when the dog is frightened to run in a rash. In this case, the locking bars will break, and the frightened dog may be injured or may injure some other people.
Increasing the cross sectional area of each locking bar without changing material tensile strength will relatively improve the tensile strength of the side release buckle. However, increasing the cross sectional area of each locking bar simultaneously makes each locking bar relatively tougher, and the user shall have to employ much more effort to unlock the side release buckle. A side release buckle having tough locking bars is not suitable for children. Using material of high tensile strength can relatively increase the tensile strength of the side release buckle. However, the material change is not the concern of the present invention.